Evil Genius has an interesting take on this trope, as main characters' design is still the same as it was in the very first strips, but new ones, as well as backgrounds, are significatly more detailed.
The art in The Rifters went from being pretty shaky and having small characters and inconsistent word buuble to looking much more professional in about 10 entries. Compare number one to number ten
Go Get a Roomie! is one that shows a rapid, but even progression of art quality that is quite staggering, to be honest. The proportions start out with very small bodies and larger heads and the lineart was done in sharp, scratchy lines. The art quickly transitions into computer-done graphics with soft, flowing, and tapering lines. Chloe goes from drawing things like This to this and this.
"God, could you imagine if someone was always changing the look of their comic?" "Eh, they probably wouldn't last very long."
Visible, not that it needed it at all from the start, in Lackadaisy. As you progress through the comic, you see the lighting becoming more expressive and detailed (thanks to computer rendering) and the characters becoming more proportionate and closer to human body types. Every panel looks like an authentic 1920's photograph.
Special mention goes to Zib. He first appeared as the one furthest to the left in the fourth panel here. Look at him now.
The Illustrated Guide To Law improved dramatically in its first year. The author has acknowledged that, at first, he didn't think anybody would be reading it, so the art was done quickly and inconsistently. But once he realized he had an audience, he started putting more effort into the art.
Sailor Moon CS completely changes its art style the second issue and changes from color to a black and white format in the forth issue
Supernormal Step has some really impressive Art Evolution. Comparing current pages with the first few shows a clear improvement in coloring, background detail, proportions, and shading. Compare Hall and Eva from their first appearance in Chapter 1 with the first page of Chapter 5.
Cwynhild's Loom has changed significantly since its beginning. The artwork can often shift significantly between updates and has leaned more towards realism over time. Cwyn's hair is a prime example.
Colour Wheel was initially started drawn on paper and coloured with marker; the artist switched to digital at the beginning of Episode 1. Also compare the art in the previous link to the art at the beginning of Episode 2.
Darkbolt: From 1999 to 2003 Sean updated his art style so that it looks way more crisp and clean than before, in 2005 he started with full color pages every weekend or every so often and by 2008 full color pages were being done a lot more.
Completely averted in Dinosaur Comics. Part of the comic's gimmick is that it always uses the exact same image for every single comic. The only thing that changes is the dialogue.
In Deviant Universe, you can see this best with artists involved in the project for a long time.
Averted in Ornery Boy in terms of character art, but definitely evolved when it comes to handling Flash.
Questionable Content is in a constant state of incremental artistic alteration, as artist Jeph Jacques likes to try out new things and use the strip as a means to improve his skills; his motto is, "If you don't like the art, come back next week, it'll probably be different". To see just how drastically his artwork has shifted over time, check out the differencebetweenthesefivestrips.
And helpfully brought into focus by the direct comparison presented here, and by thesetwo.
The style of El Goonish Shive has changed drastically over the course of its run. Compare Nanase and Justin in this strip (the redhead, and the blonde guy), and in this strip. (Yes, they are the same characters albeit one of them got a haircut.)
MegaTokyo also changed quite a while during its run, with a cartoonish style that gradually becomes more realistic and with a more detailed shading. If you want a reference, compare strips #9, #500 and #1025.
Dan and Mab's Furry Adventures is a long-running series, and over time has evolved from being very crudely drawn to being very well drawn as the artist learned how to draw. The artist herself has commented that looking back at her old art is painful.
PvP has undergone several art evolutions, which are often lampshaded. Comparing the most recent strips with the oldest ones, shows a dramatic shift in style over the years, though except for a few large leaps, these have largely been gradual changes accumulated over time.
The art style in Misfile has gone from heavily shaded, more straight-line art to a lighter and more rounded look so gradually you never notice the shift while reading it. However, it is quite jarring if you go back and read some earlier panels. Compare this to this
Lampshaded here, where the characters recap the entire events of the comic to another (mercifully offscreen).
Tom Siddell:"The first few chapters of exposition looked a little weird."
The very first Nedroid comics were hilarious, sketchy, and experimental like this one. Over time his style smoothed out. Experiments still pop up but never break too hard from the established style.
Sluggy Freelance, the first comics of this continuity appear sloppier, and the artist had a less accurate perception of human anatomy. Especially egregious in his second strip, where Torg goes from looking 12 in the first panel, 16 in the next, and finally 21 in the last panel. That, and in the first strip, Riff's looking more like a troll than anything else.
Also, primarily starting with the "Fire and Rain" arc, the format has shifted away from "three panel strips with a punchline and full-color Sunday" to longer and more dramatic layouts throughout the week. Has a lot to do with the Cerebus Syndrome.
For example, compare the art in the above early gag strip with one from the dramatic and violent "Dark Days Ahead" arc from 2002. The strip, as of this post, looks like this, although the very best artwork was probably from the (long, very dark, and spoileriffic) "That Which Redeems" arc from a few years ago.
The VG Cats artist has almost completely redesigned the way he draws the two main anthropomorphic cat characters. He has redrawn some of his old comics using his new style. Every strip looks slightly different, though there is definitely a pattern. For example, his newer stuff is a lot more animesque than his old stuff, and its pretty obvious that hes relying on his computer a lot more.
Schlock Mercenary. The creator points this out in the annotation to the very first strip, as well as providing what he apparently considers a better starting point for new Schlockers, but invites them to see his art progress from 'bad to, well, marginally less bad' by starting at the beginning.
The Adventures of Dr. McNinja started out in stark black and white. Then in issue 6, Kent Archer began shading the pages in Photoshop in addition to inking them. In issue 8, a computer problem forced Hastings and Archer to start posting updates without the proper shading. Positive reactions from a vocal portion of the fanbase led Hastings and Archer to run a poll to see if the fans preferred the comic shaded or unshaded. After the results were in, the authors Took a Third Option and hired Carly Monardo to color the comic.
Molten Blade has undergone gradual art evolution... definitely a change for the better
Drowtales has gone from quite frankly sucky art, to impressive. The early example there is even a larger step up from the original chapter 1 art than the page it's being compared to, it just kept improving.
The artists completely and utterly despise their earlier chapters and work on Drowtales and would much prefer all evidence of their earlier story and art were destroyed forever.
Earthsong's artwork improved over the years to the extent that the creator completely restarted the comic from the beginning. And, unusually for such endeavours, is still seeing it through.
The webcomics of John Allison have undergone a lot of evolution, which isn't surprising given that he's been at it for sixteen years. See Shelley, the red-haired girl in the first ever strip of Bobbins, here in 1998? By 2000 she looked like this, then this, and then Scary Go Round started, with a new artistic direction. Since then, the art has changed from digital to hand-drawn and back againtwice. The art's been fairly stable now since 2006, despite a switch from pen and ink (digitally coloured) to hand-drawing on a tablet PC.
The characters themselves get a fair bit of evolution as well — The two most obvious examples are Adharia's face (which is slowly becoming more lionlike as opposed to, say, a bear or a wolf) and Jigsaw's eye stripes, which gradually creep further down her face.
Khaos Komix has gone through an immense evolution, to the point that the author was so displeased with the old ones they rewrote and redrew them. Three times. At the moment, the art style is a bit inconsistent, as the Retcons have been done where there were plot holes, leaving patches of the previous style between newer parts. The old versions are available on download as .zip files.
Least I Could Do has had significant changes in style over the years. Compare this comic to this one, this one, this one, and this one. The style greatly changed to a more realistic, detailed, and colored one. This is less due to "the artist getting better" and more due to "changing artists several times over the course of the comic."
The evolution was demonstrated in this strip as a celebration of the 2000th strip. For record, the second from the left was the first known version of the character. It's up to Wild Man Guessing as to who the first guy is.
Girl Genius went from black-and-white to color, and Phil Foglio's skill at anatomy has also improved; for the first couple of years, he was especially prone to making character's heads too small for their bodies (Klaus and Othar were the most common victims) and the occasional giant hands or freakishly long forearms. He's straightened out now, though, and it's one of the best-looking webcomics out there.
The change from black-and-white to colour was story-driven; the change coincides with the theft of Agatha's locket, unleashing her brain
Eh, I think that's a retcon. It was a originally a self-published print comic, and the first three issues were pure black and white; the fourth, with Agatha waking up on the airship, jumps to full color.
Girl Genius has also gone through a lot of evolution when it comes to inking and coloring. While YMMV, the low point was probably the start of volume 2, where Foglio's pencils were practically un-inked and the new color was applied in eyeball-searing neon gradients. The style has gelled since, with better inking and a more subtle, attractive palette.
Although Lint is not as popular as some other examples here, the absolutely enormous difference between early, black-and-white, amateurish art such as this can barely be recognized as the gorgeous, textured masterpieces like this. And it's gotten even better if more Bishouneny.
Striptease's evolution is an insane jump from this to this
The artist for Triquetra Cats collected her evolution in this image◊
Averted for all intents and purposes with User Friendly which has gone from this to this in just under 12 years.
In Coming Up Violet, the comic has gotten noticeablybetter in the few short years it's been out. Its predecessor Fur Will Fly had quite a bit of this as well . . . possibly. It was pretty hard to tell considering just how much the art shifted from arc to arc. There were at least three different artists.
The Order of the Stick has retained its simple stick-figure art, but it has become somewhat less scratchy and smoother, and the characters occasionally have new details added to them (with Lampshade Hanging). This is a lot more noticeable in the panel lines — they started out all over the place, and now they're completely straight. The sheer detail in the background of panels, even pretty simple ones, has gone up quite a bit as well much of the time.
The character designs have also drastically improved; when the artist had to take some time off due to a hurt wrist around the hundredth strip, he took the opportunity to improve the character designs, adding details like a clasp to Elan's cape (which had been superglued to the back of his neck or something before that) and the runes around the bottom of V's cloak. Over time he has started using more standard character models, making the art far more consistent and slip-ups less frequent.
There's been another art shift as of strip 947. Arms are now flesh-colored (though still fork-shaped), sleeves and pants legs have appeared on clothes, and shoes now show a flex when characters are walking.
Narbonic and then Skin Horse. It's most obvious as you look at how Shaenon Garrity does her fills and backgrounds.
Twokinds. It started out looking like something a beginner with only a how to draw manga book as a guide, and currently is reaching near-professional quality. Just compare this this early stripwiththis later one.
The webcomic Shape Quest features a nice "upgrade" in detail following Chapter 3.
Amazingly averted in Sabrina Online, which has been running since 1996 without the art style or quality changing in any way whatsoever.
Charby the Vampirate, the author summed it up in this picture◊. She added that if she could draw as well as she does now when she started the comic, the characters would have looked like this◊.
The Doctor Who fancomic Search For the Truth began like this. Over time, the art became more clean and details and today the Doctor actually looks remarkably like David Tennant. Interestingly enough, SFTT is technically a toned-down version of the artist's style, as flipping through her gallery will yield some beautifully photo-realistic Doctor Who art. Wordlessly lampshaded here.
Juathuur has a slow but steady art evolution, that is most apparent in the passage from black and white to full color.
The FAN started with ugly thick lines, inconsistent text boxes, and lots of gradient fills. and went with them for a long time. The most changes occurred during episode 3, when the author finally learned how to use layers properly, and halfway through the episode, when the thick lines were abandoned in favor of sketchy lines due to technical issues. The latest change happened halfway though episode 4 when the sketchyness was turned down.
Planes Of Eldlor: The artist has stated that she is intentionally using this comic to evolve her skill and style, which is already somewhat evident in the comic archive.
The first 21st Century Fox strips were barely legible black and white pencil sketches, since then it has upgraded to full color and occasional animated gifs.
Bittersweet Candy Bowl shows this very clearly, going from lined paper with a simple grid layout to its current form of inventive panelling and exquisite toning.
"Selkie" has improved quite a bit, and the artist does like experimenting from time to time. Compare this and this to this and this. Whoa...
This trope can even apply to photocomics: If you take one of the older themes in Irregular Webcomic! and compare the first strip with a more recent strip (for example the Cliffhanger strips 24 and 2297), you can see how far David Morgan-Mar's photography skills and/or equipment have improved.
SPRINGIETTE style has evolved, with now much more detailed backgrounds and consistent character design.
The artwork of Josh Lesnick has been evolving constantly through his entire career as a webcartoonist, and is particularly noticeable through his time drawing Girly, a comic that started out as very animesque (much like his past projects, Wendy and CuteWendy), and eventually evolved into something more organic. This is also very noticeable in his porn comics, sometimes starring characters from Wendy.
In another mostly stick art comic, Left Handed Toons has improved considerably — particularly Drew. This is probably because the artists are getting used to drawing with their left hands. Compare this and this.
Aside from the generally improving styles over its course, Keychain of Creation pulls off a major evolution in comic #319, which goes from partial stick-figures to fully fleshed bodies. For bonus points, it hangs a huge lampshade on it by having the evolution occur as a function of Secret and Marena's sorcery initiation, implying that it's actually one of the rules of the universe.
MS Paint Adventures as a whole has undergone immense changes over time. Problem Sleuth went from this to this in a little less than a year. One year after that in the latest adventure, Homestuck, we get this update which effectively illustrates how much more skilled Hussie has become with animation since the series started.
Although Hussie's writing and animating skills noticeably improve throughout MSPA, in regards to art skills the trope is actually subverted; his drawing skills are far beyond what any of his comics, even Homestuck, actually require, so his art skills have actually gotten worse due to lack of practice.
The Other Grey Meat The characters have undergone significant changes from their original design.
Nature of Nature's Art 's 10%+ story has artwork that improved significantly near the end of the incredibly long battle between Meander and Quintet versus Rule and Polarizing. So much so that looking at the older strips is actually a little jarring, even after the artist re-drew a few.
This filler comic of The FAN illustrates how much the art has changed during the course of the first three episodes. An art shift caused a decline in quality but the comic has been recovering. This is a more recent strip, black and white, but one of the better ones.
Though the art in Ménage à 3 was good from the first issue onwards and the art style overall has remained pretty consistent for such a long-running comic, the series is slowing shifting from a straightforward Archie Comics style and occasionally incorporates a few manga features like enlarged eyes (Recent examples from end 2010):
Even Gary's had some work done, in early strips he was gangly and a little goofy-looking but now he's Adorkable and Grade-A Mr. Fanservice.
Part of that is just the audience realizing that he looks pretty good naked.
Juathuur goes from black-and-white with occasional color strips in "One Way or Another" to fully color with more fully fleshed-out character and background designs in "Gatecrash."
In Fite!, each strip has a header with portraits of the main characters. However, by the start of Round 4, the art had evolved to the point that Lucco and Guz's faces in-comic no longer matched the old header pictures. The header was updated a few strips later.
Dominic Deegan has definitely become cleaner compared to the old scribbles.
Ctrl+Alt+Del went from kind of scribbley to clean and consistent thanks to a file of body parts, and later he goes back to drawing all the characters individually. Buckley is currently experimenting with watercolor textures.
The Devil's Panties were more the scribbles of this comic personality but portions and cleaness of the lines has gotten better with time.
Tales of a Gay Asian is obviously a great example of this for 2 reasons 1.It is the creator Brian Morris's first comic and 2. Due to his busy schedule and other comics he draws 8 pages of gay asian weekly. Which attributes to the art change and how he is progressively getting better.
Archipelago starts out very scribbly in book one. Each progressive book gets a little better, with excellent quality work appearing in book 6. Compare this with this.
The creator of Dragon City and Jix is constantly improving his art to the point where the beginning of the comic doesn't really look like it was drawn by the same person as the current comic.
Freefall has seen modest amounts of art evolution, especially from the full-page magazine comics to its current webcomic form.
No Need for Bushido underwent a massive Art Evolution, going from artwork that wasn't bad, but wasn't very good, either (as seen here) to something lifted from a spectacularly well drawn cel shaded movie (as seen here, with iiiiitty bitty spoilers. Teeny tiny ones.). Thee best part is that it was a gradual shift, rather than a more sudden one.
Miscellaneous Error went through very rapid Art Evolution over its first 4 strips. It's almost as though the author was an ameteur with no prior experience or something.
Elf Blood's art has progressed in leaps and bounds over the past year of its life. Change tends to happen fairly slowly and organically, but the biggest change was also the earliest, changing to full-color from black white and screentone after a few weeks of publishing. Consistency in the art style seems to have settled in in the last story arc or so, resulting in fewer obviously off-model characters, and the backgrounds are improving in level of detail as well.
For Voodoo Walrus vast improvements have taken place since the comic first went live in 2007. Compare this comic to this. Same leading female character, same artist, but 4 years of practice can make all the difference.
Mayonaka Densha's artwork has gone from being flat and and toneless with very disproportionate characters and little to no backgrounds to this and this◊ within the space of a couple of years . The author made the choice to partially or completely redraw some of the older pages which she deemed particularly bad or inconsistent with the story, just look at the old and new pagesside by side
The artwork of Goblins: Life Through Their Eyes has changed so much over the years that the first page of the archive, rather than the first strip, is a page showing just how much the art has evolved. Most recently he has begun shading the comic to dramatic effect.
Happened to Roommates too. The early pages had a "chibi" style that gradually evolved into a more realistic and intricate (but still animesque) one. You can compare this to this.
Virtual Shackles: While the art started out somewhat close to where it is now, there have been some changes to shading, ears, and lines to make things seem sharper in general. Compare this early strip to this much later one.
Rusty and Co. demonstrates this using the original Princess sketch v.1, then The Princess as-she-appears-in-the-comic sketch v.2 where her design 'get... well, let's say "streamlined"...' — and the hypothetical v.3 — in The Order of the Stick style.
minus. At first, the eponymous character's Idiot Hair looked quite normal and possible in real life. However, very soon after that Ryan Armand starts to make minus's ahoge thicker and longer, to the point where it looks more like a ponytail than a few hairs that refuse to be combed.
It's not suprising that this is the case in Ears for Elves, given that it's the artist's first comic. The artist admits that drawing is a learning process and she's experimenting with styles and tones.
Fluffy Bunny Domination: The main character's features have notably changed, becoming less detailed with a much larger ponytail and a standard outfit. Many recent strips use the same 3 colors for the background and unnamed characters.
Useless Dumb Fucks  and the artist/writer makes fun of it a few times in the comic itself.
Compare Strip #1 to Strip #28. See a difference? Good. Now look at an even later strip, like #87. Big difference, eh?
An even more dramatic comparison is at the bottom of this page.
It later regresses, at least in detail. In chronological order: eliminating color strips altogether; eliminating almost all backgrounds or inanimate objects; positioning all characters at the same depth (with few exceptions). Color is back, for now, thanks to a fan contributor.
However, now backgrounds seem not to be as much of an issue anymore, and there's even some varied perspective.
Sonichu shows a marginal example. The art has remained consistently terrible, but in issue 5, Chris begins using some vaguely Animesque techniques such as the ^_^ expression, Cross-Popping Veins, sweat drops, and huge eyes.
Fairy Dust: Its artist has confessed learning how to draw background art through this comic, and it's rather visible, both the progression and the trial and error. Character designs are also more uniformous at the start, and gain more individuality later.
White Dark Life used to be drawn in MS paint with copious amounts of circle, rectangle, and fill tool uses before the cartoonist began using pencil and paper.
The Silver Eye started out with art that was in a somewhat-decent, but unrefined realistic style. Several chapters in, it began to develop a semi-realistic comic style, which worked much better overall. At this point the author, Laura Hollingsworth, went back and redrew half of the first chapter. It continued to improve until it became quite excellent, an the extent of Laura Hollingsworth's improvement became especially obvious when she redrew the first three pages.
The rationale behind Planet of Hats is to improve the author's drawing skills and provide entertainment.
Now that Trying Human is being redrawn from scratch for printing, you can see side by side how dramatically the art style has improved over the few years it's been running.